858
FLIGHT
A MILESTONE in Anglo-American aeronautical relations was the presentation ceremony
reported below of C.A.A. type certificates for
the first Capital Airlines Viscount, its Dart
engines and its airscrews by Mr. F. B. Lee,
administrator of the C.A.A. Left-hand scene
from the ceremony shows Lord Knollys (right)
receiving the aircraft certificate on behalf of
Vickers; seated are (left to right) Sir John
Evetts, Mr. R. E. Hardingham (partly hidden)
and Sir Colin Weedon. (Right) After the
ceremony Mr. Lee (left) was presented with
a model Viscount by Mr. Hardingham.
FROM ALL QUARTERS . . .
easy, but he paid tribute to the thoroughness and competence of
the C.A.A. team of surveyors and pilots.
Explaining in a nutshell the meaning of the C.A.A. type certificate, Mr. Lee said that "this insignificant piece of paper" represented approval of specification, structure and performance, and
conferred on the manufacturer concerned the right to enter the
market of U.S. registration. It was his belief that the interchange
of ideas between the C.A.A. and the A.R.B., with whom he had
enjoyed working, had advanced the cause of safety. He then
presented the three historic "pieces of paper"—airscrew type
certificate 890, engine type certificate 283 and aircraft type certificate 814. These were accepted on behalf of the makers of the
Rotol airscrew, the Rolls-Royce Dart 506 and the Viscount 744
by, respectively, Lt. General Sir John Evetts, managing director
of Rotol, Ltd.; Air Marshal Sir Colin Weedon, export sales
manager of Rolls-Royce, Ltd.; and Viscount Knollys, deputy
chairman of Vickers, Ltd.
. . . and More Viscount Customers
of the noise affected by the corrugations was found to depend
upon the number of corrugations, and a nozzle with six corrugations caused the largest reduction in the loudest band of the jet
noise.
The latest nozzle to be tested, say Rolls-Royce, gives a noise
reduction of 11-12 decibels, which means a reduction to less
than half and corresponds to the difference in noise heard on the
ground between an aircraft flying overhead at 1,000ft and one
flying at about 3,000ft. Development work is continuing, and
when the optimum point is reached production will be arranged
and engines fitted with these nozzles made available.
All this work has been done on a specially designed testbed, but a set of nozzles has now been made for the de Havilland
Comet and will be flight tested in the near future.
Corrugated nozzles, it is stated, can be supplied with similar
success to the Conway by-pass engine, which, even with a nozzle
of the normal kind is much quieter than conventional turbojets.
Corrugated-nozzle jet silencer
by Rolls-Royce.
IVE new Viscount contracts have been announced by VickersFArmstrongs
over the last few days, bringing the total number
of aircraft sold to 227. The new customers are B.O.A.C., K.L.M.,
Howard Hughes Tool Company and Standard Oil Company
of California, and Fred Olsen Airtransport have placed a repeat
order. Full details of the new contracts are given on page 884.
Rolls-Royce Turbojet Silencing
the firms who, at the request of the Ministry of
AMONG
• Supply, have been conducting research into the problems
of jet noise is Rolls-Royce, Ltd. Last week they disclosed interim results of their work and released a photograph—reproduced here—of a corrugated nozzle which has given encouraging
results.
Introducing a note on the subject with the forceful reminder
than an engine of 10,000 lb thrust generates about 100 h.p. in
noise energy, Rolls-Royce say that the corrugated-nozzle system
was arrived at after early experiments that met with only limited
success. (An essential requirement is that any such device must
not only effect a useful noise-reduction, but must do so without
detriment to engine performance.)
A range of nozzles with different numbers of corrugations
from sixty to four was made and tested. The results were most
encouraging; the jet noise was reduced and, carefully designed,
the nozzles did not affect the engine performance. The pitch
Power for the DC-8
"COLLOWING the announcement, last week, ihat Douglas
• Aircraft had decided that the time was ripe to go ahead with
their DC-8, news has been received that Mr. Nat Paschall and
Mr. Ivar Shogram, respectively vice president for commercial
sales and chief project engineer for the
DC-8, were to arrive in London last
Wednesday for visits and discussions about
the new jet airliner. Apparently Mr. Shogram, who was previously Douglas powerplant group chief, has indicated his special
interest in the Rolls-Royce Conway.
According to the Douglas release about
the visit of the company's two executives
"original announcements of the DC-8 said
it would be powered by four Pratt and
Whitney J-57 turbojet engines. . . ." The
pointed re-quotation of this paragraph may
or may not be intended as an official broad
hint about Douglas powerplant thinking.
The DC-8 at the quoted 257,000 lb. a.u.w.
PARIS AERO SHOW ARRIVAL: The Bristol 173,
flown by C. 7". D. Hosegood, landing at Le
Bourget airport exactly two hours after leaving
the South Bank site in London.